Question 1

Which of the following best describes the evolutionary significance of cephalization in animals?

Accepted Answer

It clusters neurons for sensory and integration roles, leading to the formation of complex brains.

Question 2

Which division of the peripheral nervous system is primarily responsible for regulating the contraction of smooth and cardiac muscle?

Accepted Answer

Autonomic system

Question 3

A patient is experiencing increased heart rate and dilated pupils after a car accident. Which division of the autonomic nervous system is most likely activated?

Accepted Answer

Sympathetic division

Question 4

Which of the following correctly matches the nervous system structure with its function?

Accepted Answer

Central nervous system: Integrates sensory information and coordinates responses

Question 5

Which process directly requires ATP during skeletal muscle contraction?

Accepted Answer

Release of myosin head from actin filament

Question 6

What is the immediate effect of acetylcholine release at the neuromuscular junction?

Accepted Answer

It causes the muscle membrane to depolarize, initiating an action potential.

Question 7

Which of the following best explains why Ca$$^{2+} is $$essential for muscle contraction?

Accepted Answer

Ca$$^{2+}$$ binds to the troponin complex, exposing actin binding sites for myosin.

Question 8

A drug that prevents the release of acetylcholine at the neuromuscular junction would most likely result in which of the following?

Accepted Answer

Muscle paralysis due to lack of depolarization

Question 9

Which of the following sequences correctly describes the events leading to skeletal muscle contraction?

Accepted Answer

Action potential → Acetylcholine release → Muscle membrane depolarization → Ca$$^{2+}$$ release → Troponin binding → Myosin-actin interaction

Question 10

Which component of the autonomic nervous system is most active during digestion and rest?

Accepted Answer

Parasympathetic division

Question 11

If a mutation caused the troponin complex to be unable to bind Ca$$^{2+}$$, what would be the most likely effect on muscle contraction?

Accepted Answer

Myosin would not be able to bind actin, preventing contraction.

Question 12

Which of the following best describes the role of ganglia in annelids and arthropods?

Accepted Answer

They serve as clusters of neurons for localized processing within body segments.

Question 13

Which of the following is a correct statement about the structure of skeletal muscle?

Accepted Answer

A muscle fiber is a bundle of myofibrils segmented into sarcomeres.

Question 14

A person is exposed to a toxin that blocks the reuptake of Ca$$^{2+}$$ into the sarcoplasmic reticulum. What is the most likely physiological outcome?

Accepted Answer

Muscle fibers will remain contracted due to persistent exposure of actin binding sites.

Question 15

Which of the following best explains why the enteric division of the autonomic nervous system is sometimes called the 'second brain'?

Accepted Answer

It can function independently to regulate the digestive tract, pancreas, and gallbladder.

Question 16

Which of the following is a function of the peripheral nervous system (PNS)?

Accepted Answer

Transmitting information to and from the central nervous system

Question 17

During a laboratory experiment, a student applies a chemical that prevents ATP hydrolysis in muscle fibers. What is the most immediate effect on muscle contraction?

Accepted Answer

Myosin heads will remain bound to actin, preventing muscle relaxation.

Question 18

Which of the following best describes the role of the motor system within the peripheral nervous system?

Accepted Answer

It carries signals to skeletal muscles for voluntary and involuntary contraction.

Question 19

Which of the following events marks the end of a muscle contraction?

Accepted Answer

Depolarization of the muscle membrane closes Ca$$^{2+}$$ channels, reducing cytosolic Ca$$^{2+}.$$

Chapter 20: Motor Mechanisms and the Nervous System: Structure and Function

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